It is well known that electric power tools are used extensively in manufacturing and service industries. Additionally, hand tools of such nature are routinely used by the home craftsman and handyman. Typically, such power tools are switch actuated and controlled. Hand tools generally employ a trigger switch to control the on/off function which may also include variable speed control. Presently, such trigger switches are generally spring biased to the "off" position such that release of the trigger switch results in a termination of operation of the hand tool. Such biased switches are often referred to as "deadman" switches since termination of control by an operator over the switch deactuates the switch.
Even when a deadman switch is employed, it is known that when the trigger of the switch is released the inertia and back EMF of the motor causes the same to continue to rotate or run until the inertia and/or back EMF is dissipated. Such characteristics of motors often defeat the purpose and intent of the deadman feature of the switch. In the prior art, there is generally not provided a brake on the motor such that the termination of electrical power to the motor assures immediate termination of motor rotation.
There is a need in the art for an immediate and reliable shorting of the motor coils to instantaneously dissipate the back EMF of the motor upon termination of power thereto, thereby locking the motor rotor. Indeed, there is a need in the art for a dynamic brake for a motor, which dynamic brake may be efficiently and effectively maintained in the trigger switch housing.